CODEWITHSUNDEEP
coffeescript
rafaelcosman
rafaelcosman

Reputation: 2599

How to use setTimeout() in Coffeescript

I can't seem to use setTimeout() to call one of my own functions. I can use setTimeout to call alert(), but not a function that I've written myself. Here's the simplest code that reproduces the problem:

I have the following coffeeScript

    setTimeout(run, 1000)

    run = () ->
        console.log("run was called!")

Which generates the following Javascript

    // Generated by CoffeeScript 1.6.3
    (function() {
      var run;

      setTimeout(run, 1000);

      run = function() {
        return console.log("run was called!");
      };

    }).call(this);

Nothing is printed to the console.

Upvotes: 26

Views: 22353

Answers (2)

cwd
cwd

Reputation: 54856

Anonymous Option:

Peter is exactly right. But you can also use setTimeout without declaring a variable:

setTimeout ->
    console.log 'run was called!'
, 1000

Yields:

(function() {
    setTimeout(function() {
        return console.log("run was called!")
    }, 1e3)
}).call(this);

Upvotes: 23

Peter Lyons
Peter Lyons

Reputation: 146174

run = () ->
    console.log("run was called!")
setTimeout(run, 1000)

You are relying on javascript function hoisting for functions declared with the syntax function run(){}, but coffeescript declares them as variables: var run = function(){}, so you have to define the function before you reference it, otherwise it's still undefined when you pass it to setTimeout.

Upvotes: 27

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